Cable reel

Abstract: A cable reel of the present invention uses a tape-shaped cable including a high-strength conductor having a high-strength conductor having a tensile strength of 500 to 1500 N/mm², an elongation percentage of 0.5 to 50 % and a spring limitation value of 400 to 2000 N/mm². Accordingly, in such a cable reel, weight as well as in cost of the whole of parts in a cable reel can be reduced.

Description: 1. Field of the Invention The present invention relates to a cable reel adapted for performing electrical connection between a stationary matter and a movable matter by using a tape-shaped cable and particularly relates to a cable reel suitable for use in a steering apparatus of a vehicle. 2. Description of the Related Art A cable reel according to the preamble of claim 1 is shown in Fig. 4 of US 49 75 063. DE 42 36 279 A1 shows a cable reel with a cable accommodated in a housing in a bifilar manner with a sharp 180° turn, which travels along the cable during rotating action. The conductor of the cable is made of a beryllium copper alloy. For example, when signal transmission is performed between the handle side of a car and the car body side of the car, such a device as shown in Fig. 1 is used. Namely, a tape-shaped cable is spirally housed in a housing having an inner cylinder and an outer cylinder so that the rotation of a handle is absorbed by tightening and loosening of the winding of the tape-shaped cable. Recently, requirements for reduction of weight of car parts and for reduction in cost thereof have been increased more strongly. The case of a cable reel is not exceptional. To attain the weight reduction of the cable reel and the cost reduction thereof, it is necessary to make the tape-shaped cable thinner, and to this end, it is necessary to make the conductor thinner. When ordinary tough pitch copper is used as the conductor and such copper is made thinner, there arises a problem that durability against repeated rotation is lowered. SUMMARY OF THE INVENTION It is an object of the present invention to provide a cable reel in which a tape-shaped cable is effective for reduction of the weight and cost of the cable reel without lowering the durability against rotation in spite of the reduction in thickness. In order to achieve the above object, the cable reel of the present invention comprises a housing including an inner cylinder having a first opening therein and an outer cylinder having a second opening therein; and a tape-shaped cable which is spirally housed in said housing, both end portions of said tape-shaped cable being led to the outside of said cable reel through said first opening and said second opening respectively; wherein said cable reel allows absorbing of relative rotations between said inner and outer cylinders by tightening or loosening of windings of said tape-shaped cable. Preferred embodiments are shown in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings; Fig. 1 is a view showing a condition before a cable reel of the present invention is assembled; and Fig. 2 is a perspective view showing one example of a tape-shaped cable. PREFERRED EMBODIMENTS OF THE PRESENT INVENTION The preferred embodiments of the present invention will be described referring with the accompanying drawings. A preferable tape-shaped cable used in the present embodiment includes a plurality of conductors therein. For example, six conductors are laminated between insulated materials with adhesive from the upper and lower sides thereof as shown in Fig. 2. As shown in Figs. 2, the tape-shaped cable 3 includes conductors 11 and insulative members 12 for laminating each other to hold the conductors 11 therebetween. As shown in Fig. 1, the cable reel includes a housing having an outer cylinder 2, inner cylinder 1 and holder 8, and the tape-shaped cable 3 housed therein. An end holding portion 4 of the tape-shaped cable 3 is held by the inner cylinder 1 and holder 8. A beginning holding portion 5 of it is held by the outer cylinder 2. The end holding portion 4 and beginning holding portion 5 are introduced to the outside of the housing through an inner cylinder hole 6 and outer cylinder hole 7, respectively, so as to connect to a control unit, circuit of an inflator or the like. The outer cylinder 2 and inner cylinder 1 are supported rotatively to each other. Further, the inner cylinder 1 is fixed so as to rotate in accordance with the rotation of a handle of a vehicle or the like. In this state, the inner cylinder 1 is rotated in accordance with the rotation of the handle, however such a rotation is absorbed by spirally tightening and loosening of the winding of the tape-shaped cable 3, so that the electrical connection through the tape-shaped cable 3 can be always maintained. In such a tape-shaped cable, polyester or PET (polyethylene terephtalete) film is preferably used as the insulative member. Preferable conductive material used as the conductor is copper foil, tin plated copper foil, copper-tin alloy, copper-silver alloy or the like. Further, a preferable conductor of the embodiment has a tensile strength of 500 to 1500 N/mm 2 , preferably 500 to 900 N/mm 2 , elongation percentage of 0.5 to 50 %, preferably 0.5 to 10 %, spring limitation value (Japanese Industrial Standard H3130) of 400 to 2000 N/mm 2 , preferably 400 to 700 N/mm 2 , and thickness of 0.01 to 0.1 mm, preferably 0.03 to 0.1 mm. The conductor of a tape-shaped cable is effective for reduction of the weight and cost of the cable reel without lowering the durability against rotation in spite of the reduction in thickness. EXAMPLES With respect to fourteen kinds of conductors shown in Table I, tape-shaped cables were prepared respectively as examples or comparative example of this embodiment. Each of the tape-shaped cables was produced by arranging 1.0 mm-wide six conductors in parallel at intervals of a pitch of 1.5 mm and then laminating the conductors with polyester tapes with adhesive from the upper and lower sides thereof. By using these tape-shaped cables, the respective motions of the tape-shaped cables in the cable reel were simulated so that durability against rotation was tested. Results of the test were as shown in the right-end column of Table I. As shown in Table I, in the case where each of high-strength conductors Nos. 1 to 7 having a tensile strength of 500 to 900 N/mm 2 , an elongation percentage of not 0.5 to 7.0 % and a spring limitation value of 400 to 700 N/mm 2 is used as the conductor, a good result that durability against rotation is not smaller than 3,000,000 times is obtained though the thickness of the conductor is reduced to be in a range of from 0.1 mm to 0.03 mm, so that there arise remarkable effects for reduction in weight as well as cost of the cable reel.

Claims: A cable reel comprising: a housing including an inner cylinder (1) having a first opening (6) therein and an outer cylinder (2) having a second opening (7) therein; and a tape-shaped cable (3) which is spirally housed in said housing, both end portions (4,5) of said tape-shaped cable (3) being led to the outside of said cable reel through said first opening (6) and said second opening (7) respectively; wherein said cable reel allows absorbing of relative rotations between said inner and outer cylinders by tightening or loosening of windings of said tape-shaped cable, characterized in that said tape-shaped cable comprises a high-strength conductor (11) having a tensile strength of from 500 to 1500 N/mm 2 , an elongation percentage of 0.5 to 50 % and a spring limitation value of 400 to 2000 N/mm 2 . A cable reel according to claim 1, wherein the thickness of said conductor (11) is from 0.01 to 0.1 mm. A cable reel according to claim 1, wherein said tape-shaped cable includes a plurality of conductors (11) and insulating members (12) laminated together, holding said conductors therebetween.

Inventors: SAEN HARUO, SAKAMOTO YOSHITO, SAEN, HARUO, SAKAMOTO, YOSHITO, SAEN, HARUO, C/O KANTOH WORKS OF, SAKAMOTO, YOSHITO, C/O KANTOH WORKS OF
Applicants: SUMITOMO ELECTRIC INDUSTRIES, SUMITOMO ELECTRIC INDUSTRIES, LTD.
Application year: 1994
Main classification: H01R35
IPC codes: B60R16, H02G11, H01R35